According to this Gama story, THQ is suing Activision over alleged similarities between box art of SCORE International Baja 1000 and Baja Edge of Control.
THQ claims it has already spent $1 million promoting its game. Apparently it's already asked Activision to make changes to the art on the cover of SCORE International Baja 1000, but has been met with refusal.
As you can see through the link, it wouldn't take a gigantic leap of logic to see that THQ may have a case. Just saying, like.
Take a look.